JP5318441B2 - Sewing machine threading device - Google Patents

Abstract

A threading device of a sewing machine is provided. The threading device includes a threading hook which moves forward to penetrate through an eye of a needle to capture a thread and which moves backward to insert the thread into the eye, a threading shaft which holds the threading hook at a lower end thereof, a threading movement input mechanism from which an operation for causing the threading hook to carry out a threading movement is input, an up-and-down member which moves, in accordance with the operation to the threading movement input mechanism, in up and down directions to rotate the threading shaft, a thread holding mechanism which holds the thread to be inserted into the needle, and a thread releasing mechanism which releases the thread that is held by the thread holding mechanism. The thread releasing mechanism releases the thread when the threading hook is moving backward.

Description

  The present invention relates to a threading device for a sewing machine.

A conventional threading device for a sewing machine includes a threading shaft that rotates to advance a threading hook provided at a lower end portion in a threading operation direction, and an elevating operation that imparts a rotating operation to the threading shaft by a lowering operation. A member, a holding part for holding a sewing thread for threading, and a release lever for releasing the sewing thread held by the holding part in accordance with the lowering operation of the elevating member are provided (for example, see Patent Document 1).
The holding portion includes a thread guide plate that guides the sewing thread to the thread holding position, a holding plate that holds the thread in cooperation with the thread guide plate, and a spring that presses the holding plate toward the thread guide plate. The plate is rotatably supported against the thread guide plate against the spring.
The release lever is rotatably supported in contact with the descending elevating member, and has a release portion that engages with the holding plate and promotes rotation on the rotating end side.
Thus, at the time of threading, the elevating member moves downward, the release lever rotates by contacting the descending elevating member, the release portion of the release lever is engaged with the holding plate, and the holding plate is spring-loaded. Rotate against As a result, the holding plate is opened and the sewing thread is released, and then the threading hook is advanced by the lowering operation of the elevating member to penetrate the hole of the sewing needle, and the released sewing thread is captured and moved backward. The threading hook pulls the sewing thread into the eye hole of the sewing needle, and threading is performed.
Japanese Patent No. 3666339

However, the above-described conventional threading device is released as soon as the elevating member starts to descend, and the sewing thread is released before the threading hook penetrates the eye of the sewing needle and captures the sewing thread. End up. For this reason, when the thread is caught by the threading hook, the thread is removed from the moving path of the threading hook, and the thread cannot be caught by the threading hook, and there is a problem that the threading cannot be reliably performed. there were.
In addition, since the conventional threading device has a structure in which the holding plate is swung from the moving table via the release lever, the number of parts is large and the mechanism is complicated, so that malfunction is likely to occur and the cost of the device is reduced. There was a problem such as high.
Further, since the sewing thread is held in a state of being clamped by the clamping member, it is difficult for an operator to visually recognize the clamping state, and there is a problem that it is impossible to prevent the occurrence of poor clamping.

  An object of the present invention is to perform proper threading.

  According to the first aspect of the present invention, the threading hook that passes through the eye hole of the sewing needle by the forward movement and captures the sewing thread, and the sewing thread captured by the backward movement is inserted into the eye hole, and the threading hook is held at the lower end. A threading shaft, a threading operation input mechanism for inputting an operation for causing the threading device to perform a threading operation, and an operation to the threading operation input mechanism move up and down to rotate the threading shaft. An elevating member to be applied, a thread holding mechanism for holding a sewing thread inserted through the sewing needle by a clamping portion urged by a first elastic member, and the sewing thread held by the thread holding mechanism. A threading device for a sewing machine comprising: a thread release mechanism for releasing the sewing machine; wherein the elevating member includes a second elastic member that engages with the holding portion when the elevating member moves in the vertical direction. When the member descends, The second elastic member is engaged so as to act in a direction in which the sewing thread of the clamping portion is not released, and when the elevating member is raised, the second elastic member pushes the clamping portion of the sewing thread. The sewing thread is biased in the releasing direction, and the sewing thread is released when the threading hook moves backward.

The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and passes through the eye hole of the sewing needle by forward movement to capture the sewing thread, and inserts the sewing thread captured by backward movement into the eye hole. By a threading hook, a threading shaft that holds the threading hook at the lower end, a threading operation input mechanism that inputs an operation that causes the threading device to perform a threading operation, and an operation to the threading operation input mechanism. A thread holding member that moves in the vertical direction and holds the sewing thread inserted into the sewing needle by the clamping member biased by the first elastic member, and the lifting member that rotates the threading shaft. In a threading device for a sewing machine comprising a mechanism and a thread release mechanism for releasing the sewing thread held by the thread holding mechanism, an engagement member provided on the elevating member, and when the elevating member moves in the vertical direction , The lifting member A second elastic member provided on the holding member so as to engage with the engaging member, and when the elevating member is lowered, the second elastic member is formed by the sewing thread of the holding portion. When the elevating member is engaged so as to act in a direction not released, the second elastic member urges the clamping part in a direction to release the sewing thread,
The sewing thread is released when the threading hook moves backward.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and further includes a regulating member that reduces the amount of bending of the second elastic member.

  The invention described in claim 4 has the same configuration as that of the invention described in any one of claims 1 to 3, and the holding portion includes two holding members having holding surfaces facing each other, and is held. A window portion through which the sewn thread can be visually recognized is provided in at least one of the clamping members.

  According to the first aspect of the present invention, the sewing thread held by the thread holding mechanism is released after the threading hook catches the sewing thread. Therefore, when the threading hook catches the sewing thread, the sewing thread comes off from the moving path of the threading hook. Therefore, the threading hook can reliably catch the sewing thread, and the reliability of the threading operation can be improved. Also, unlike the conventional case where the thread release is performed via another member that performs a different operation from the member that imparts the movement of the threading hook, the operation transmission structure can be simplified. The apparatus becomes inexpensive and it is possible to suppress malfunctions.

  According to the second aspect of the present invention, since the thread holding hook releases the sewing thread held by the thread holding mechanism after the sewing thread is captured, when the threading hook captures the sewing thread, the sewing thread is removed from the moving path of the threading hook. Therefore, the threading hook can reliably catch the sewing thread, and the reliability of the threading operation can be improved. Also, unlike the conventional case where the thread release is performed via another member that performs a different operation from the member that imparts the movement of the threading hook, the operation transmission structure can be simplified. The apparatus becomes inexpensive and it is possible to suppress malfunctions.

  According to the third aspect of the present invention, since the restricting member reduces the amount of bending that occurs in the second elastic member at the time of engagement when it is raised compared to when it is raised when the elevating member is lowered, the second elasticity The force with which the member biases the clamping member is increased. For this reason, it is possible to reliably increase the force with which the elastic member urges the clamping member than the force of the first elastic member that urges the clamping member in the direction to clamp the sewing thread. Can release the sewing thread without fail.

  In the invention according to claim 4, since the window portion through which the sewing thread can be visually recognized is provided on the clamping member, the holding state of the sewing thread can be visually confirmed, and the occurrence of poor threading due to unintentional dropping of the sewing thread is suppressed. Is possible.

(Whole structure of sewing machine threading device)
A sewing machine threading device 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the threading device 10, FIG. 2 is a front view, FIG. 3 is a front view excluding some components, and FIG. 4 is a plan view excluding some components.
The sewing machine on which the threading device 10 is mounted is a sewing machine that can realize both overlock and cover stitch sewing with a single machine, and includes five sewing needles 1 to 5 and is used for overlock sewing. The two sewing needles 1, 2 are arranged in a line in a plan view, and the three sewing needles 3, 4, 5 used for cover stitch sewing are arranged in a line in a plan view. The sewing needles 1 and 2 and the sewing needles 3, 4, and 5 are arranged in parallel with each other but are offset in a direction orthogonal to the arrangement direction. Each sewing needle 1 to 5 is held by one needle bar 6.
In the following description, the direction parallel to the needle bar 6 is the Z-axis direction, the direction perpendicular to the needle bar 6 and the arrangement direction of the sewing needles 1, 2, 3, 4, 5 is the X-axis direction (first The direction perpendicular to the needle bar 6 and also perpendicular to the X-axis direction is defined as the Y-axis direction (second direction).

The threading device 10 is mounted on the surface of the sewing machine and is disposed adjacent to the needle bar 6.
The threading device 10 includes a threading shaft 11 that holds a threading hook 20 that penetrates into the eye holes of the sewing needles 1 to 5 by advancement and inserts the sewing thread captured by retreating into the eye holes, and the threading shaft 11. A threading operation input mechanism 300 for imparting forward / backward movement of the threading hook 20, a thread holding mechanism 50 for retaining the sewing thread in an arrangement opposite to the threading hook 20 with the sewing needles 1 to 5 interposed therebetween, and a thread A thread holding mechanism that supports the holding mechanism 50 so as to be movable between a threading position that is the opposite side of the threading hook 20 across the sewing needles 1 to 5 and a standby position that is separated from the sewing needles 1 to 5. A support mechanism 60, a thread release mechanism 70 that releases the sewing thread held by the thread holding mechanism in accordance with the backward movement of the threading hook 20, and a first support mechanism that supports the threading shaft 11 so as to be movable in the X-axis direction. 100 and threading shaft 11 The threading shaft 11 is moved along a locus corresponding to the arrangement of the sewing needles 1 to 5 by an input operation to the second support mechanism 200 that is movably supported in the Y-axis direction and the movement operation lever 441 as a movement operation unit. And a main frame 90 that supports each component.

(Threading shaft and threading hook)
FIG. 5 is an enlarged perspective view of the lower end portion of the threading shaft 11.
The threading shaft 11 has a round bar shape as shown in FIGS. 1 and 2, and is disposed in the vicinity of the needle bar 6 in parallel with the needle bar 6 along the Z-axis direction.
A threading hook 20 is provided at the lower end of the threading shaft 11 via a hook holding arm 21. The hook holding arm 21 extends in the radial direction of a circle centered on the threading shaft 11 and downward.
The threading hook 20 is provided at the tip of the hook holding arm 21 and is provided to extend in a tangential direction of a circle with the threading shaft 11 as the center. Since the threading hook 20 is disposed in a tangential direction on the circumference around the threading shaft 11, the forward end of the threading shaft 11 moves forward by forward rotation of the threading shaft 11. And reverse by reverse rotation.
Further, the threading hook 20 is formed with a hook-like barb at its tip, and is inserted into the eye holes of any of the sewing needles 1 to 5 from the tip during advance, and the tip is returned. The sewing thread is captured, and the thread that has been captured during retraction is pulled into the eye hole and threading is executed.

A pair of guide plates 22 and 23 are provided at both ends of the thread holding hook 20 at the front end portion of the hook holding arm 21 and the flat plate surfaces thereof are substantially parallel to both the threading hook 20 and the threading shaft 11. It has been. The guide plates 22 and 23 are curved in a shape that spreads toward the distal end portion, and the distance between them is set slightly wider than the thickness of a normal sewing needle. Such guide plates 22 and 23 can correctly guide the eye holes of any one of the sewing needles 1 to 5 to the threading hook 20 during forward movement.
Further, each guide plate 22, 23 is formed with a sewing thread guide notch at a position slightly lower than the threading hook 20 along the extending direction of the threading hook 20. It is possible to guide the threading hook 20 to an appropriate height and to catch it.

(main frame)
FIG. 6 is a perspective view schematically showing a support structure among the main frame 90, the first support mechanism 100, and the second support mechanism 200.
As shown in FIGS. 1, 4, and 6, the main frame 90 is a structure formed by sheet metal processing, and is fixedly mounted on a sewing machine frame (not shown). The main frame 90 is configured by fixedly connecting a substantially planar back plate 91 and a front frame 92.
The back plate 91 is fixedly supported by the sewing machine frame so that the flat plate surface is along the XZ plane, and holds the main structure of the positioning mechanism 400 on the back side.
The front frame 92 is a plate-like body along the XZ plane that is in close contact with the front side of the back plate 91, and the second support mechanism 200 is disposed in a region on the front side of the sewing machine. A first support mechanism 100 is disposed on the front side of the sewing machine.

(Second support mechanism)
As shown in FIGS. 4 and 6, the second support mechanism 200 is a substantially plate-like structure formed by sheet metal processing, and is supported by the main frame 90 so as to be movable in the Y-axis direction. Two frame bodies 201, a pair of guide shafts 202 erected along the Y-axis direction from the back surface of the second frame body 201, and a pair of cylindrical shapes provided on the main frame 90 to insert and support the guide shaft 202 And a support portion 203.

Each guide shaft 202 is inserted into each cylindrical support portion 203 provided on the main frame 90 and can slide within the cylindrical support portion 203. Accordingly, the second frame 201 can be freely slid along the Y-axis direction with respect to the main frame 90.
That is, the second support mechanism 200 can move all the configurations supported by the second frame body 201 in the Y-axis direction.
Further, a bracket-like motion transmission arm 206 extending to the back side is erected on the back side of the second frame 201 along the Y-axis direction. The motion transmission arm 206 extends to the back side of the back plate 91 through a through hole 90a provided in the main frame 90, and the tip thereof is connected to a positioning mechanism 400 described later.
That is, the second frame 201 receives a moving force along the Y-axis direction from the motion transmission arm 206.

(First support mechanism)
As shown in FIGS. 3, 4, and 6, the first support mechanism 100 is a first frame body supported so as to be movable in the X-axis direction with respect to the second frame body 201 of the second support mechanism 200. 101, a pair of guide shafts 102 that connect the first frame body 101 to the second frame body 201 so as to be movable in the X-axis direction, and a second frame body 201 that supports the guide shaft 102 And a pair of support arm portions 103.

  As shown in FIGS. 3 and 6, two support brackets 107 are provided in the lower part on the front side of the first frame 101 so as to be lined up and down. Each support bracket 107 is formed along an XY plane, and an insertion hole 107a for inserting the threading shaft 11 is formed at a concentric position along the Z-axis direction. The threading shaft 11 is inserted into the insertion holes 107a to support the threading shaft 11 so as to be movable in the vertical direction.

  In addition, guide holes 104 are formed in the vicinity of the back surface of the first frame body 101 along the Y-axis direction at the upper and lower portions thereof. On the other hand, support arm portions 103 that are bent up along the YZ plane are formed at the left and right ends of the upper and lower portions of the second frame 201, and a pair of left and right guide shafts 102 are formed. Is held along the X-axis direction. The first frame 101 is supported by the support arm portions 103 of the second frame 201 with the guide shafts 102 inserted into the guide holes 104, whereby the first frame 101 is The frame 201 can be slid along the guide shaft 102 in the X-axis direction. That is, the first support mechanism 100 can move all the configurations supported by the first frame 101 with respect to the second frame 201 in the X-axis direction. Therefore, all the configurations supported by the first frame 101 with respect to the main frame 90 are supported in the X-axis direction and the Y-axis direction by the cooperation of the first support mechanism 100 and the second support mechanism 200. It can be moved arbitrarily.

Further, as shown in FIGS. 4 and 6, a pair of upper and lower power transmission brackets 109 extend along the XY plane at the upper left portion of the first frame 101. A swing arm 423 of a positioning mechanism 400, which will be described later, is connected between the motion transmission brackets 109 via a support shaft 423b along the Z-axis direction.
That is, the first frame 101 receives a moving force from the motion transmission bracket 109 along the X-axis direction.

(Positioning mechanism: overall configuration)
The positioning mechanism 400 will be described with reference to FIGS. 7 is a perspective view of the threading device viewed from a direction different from that of FIG. 1, FIG. 8 is a rear view of the threading device partially omitted, and FIG. 9 is a view of the step switching unit 410 of the moving operation lever 441 viewed from the right side. FIG. 10 is a side view, and FIG. 10 is an explanatory diagram showing the stage switching positions by developing the cams 421 and 431.
Each component of the positioning mechanism 400 is supported mainly on the back side of the back plate 91 of the main frame 90.
The positioning mechanism 400 moves in order to perform a step-by-step switching operation for each sewing needle 1 to 5 and a 441 operation input unit 440 for sequentially inputting the position switching operation of the threading shaft 11 to each sewing needle 1 to 5. A stage switching unit 410 that intermittently divides the rotation operation of the operation lever 441, and a first cam that imparts a movement operation along the X-axis direction to the threading shaft 11 by an input operation of the movement operation lever 441 of the operation input unit 440. A mechanism 420 and a second cam mechanism 430 that imparts a movement operation along the Y-axis direction to the threading shaft 11 by an input operation of the movement operation lever 441 are provided.

(Positioning mechanism: operation input section and stage switching section)
The operation input unit 440 includes a first rotation support shaft 442 that is rotatably supported along the X-axis direction on the back surface side upper portion of the back plate 91, and one end portion (left end portion) of the first rotation support shaft 442. A selection operation lever 441 fixedly mounted on the main shaft, a main drive gear 443 fixedly mounted on the other end (right end) of the first rotation support shaft 442, and a second rotation support of the first cam mechanism 420 described later. And a passive gear 444 fixed to the shaft 422.
The selection operation switching lever 441 includes a lever portion 441a extending in a rod shape toward the outside in the radial direction of a disk partially cut out in a straight line, and the first rotation support shaft 441 at the center position of the disk. It is fixed to.
Further, the main driving gear 443 meshes with the passive gear 444. The main driving gear 443 is fixedly mounted on the first rotation support shaft 442, and when the selection operation lever 441 is rotated, rotational torque is applied to the second rotation support shaft 433 via the driven gear 444. Then, the first cam mechanism 420 is operated.
In the above configuration, the selection operation switching lever 441 is disposed on the right side and the rear side (rear side) of the sewing machine frame, and the lever portion 441a is disposed so as to protrude from the rear side (rear side) of the sewing machine cover.

In addition, a rotating body 411 of the stage switching unit 410 is provided at an intermediate position of the first rotation support shaft 442. That is, as shown in FIG. 9, the stage switching unit 410 is fixedly supported by the first rotation support shaft 442, and has a locking recess 412 to 416 corresponding to each sewing needle 1 to 5 on the outer periphery. 411 and a leaf spring 417 that fits in each of the locking recesses 412 to 416 and restricts the rotation of the rotating body 411.
The leaf spring 417 has an engagement protrusion formed at the tip, and is attached to the back plate 91 in a state where the engagement protrusion is urged to press the rotating body 411. For this reason, when the movement operation lever 441 is rotated, the engagement protrusions sequentially enter the respective locking recesses 412 to 416 provided on the outer periphery, and the rotation is restricted each time. That is, the turning operation is performed intermittently. In addition, the angular interval of each engagement recessed part 412-416 is set so that the amount of rotation operation between each locking recessed part 412-416 becomes the operation amount required for the movement of the threading shaft 11 between each sewing needles 1-5. Is set.

(Positioning mechanism: first cam mechanism)
The first cam mechanism 420 is rotated with the second rotation support shaft 422 and the second rotation support shaft 422 that are rotatably supported while facing the X-axis direction on the back surface side of the back plate 91. The first cam 421 (not shown in FIG. 4) that is a groove cam supported by the first cam 421 and a protrusion 423a that is a cam follower that engages with a cam groove 421a formed on the outer periphery of the first cam 421. A moving arm 423.
The first cam 421 has a cylindrical shape, and a substantially spiral cam groove 421a is formed on the outer peripheral surface thereof. FIG. 8 shows a state in which the follower projection 423a is positioned at one end of the cam groove 421a, and the threading hook 20 supported by the threading shaft 11 at this position is threadable through the sewing needle 1. ing.
The swing arm 423 is connected to a power transmission bracket 109 provided on the first frame 101 via a support shaft 423b provided on the other end. As shown in FIG. 4, the power transmission bracket 109 is formed with an elongated hole 109a along the Y-axis direction, and the support shaft 423b of the swing arm 423 is inserted into the elongated hole 109a.
When the first cam 421 rotates clockwise as viewed from the left, the follower protrusion 423a of the swing arm 423 is given a moving force in the X-axis direction (right direction). As a result, the other end of the swing arm 423 moves to the left, and the first frame body 101 moves to the left via the power transmission bracket 109. Further, when the first cam 421 rotates in the reverse direction, the first frame 101 moves in the right direction.
The elongated hole 109a of the power transmission bracket 109 allows a displacement in the Y-axis direction that occurs when the other end portion of the swing arm 423 is rotated, and the second frame body 201 by the second cam mechanism 430 described later. This is to allow movement of the first frame 101 in the Y-axis direction accompanying movement in the Y-axis direction.

(Positioning mechanism: second cam mechanism)
The second cam mechanism 430 faces the X-axis direction on the back side of the back plate 91 and the second cam 431 that is a linear cam that moves along the X-axis direction along with the swing of the swing arm 423. A third rotation support shaft 432 that is rotatably supported in a state, and a rotation support shaft 432 that converts the linear motion operation of the second cam 431 into a rotation operation to form a third rotation support shaft 432. A substantially L-shaped link member 434 that imparts a movement operation in the Y-axis direction to the second frame body 201 via the operation transmission arm 206 by the rotation of the follower protrusion 433 that transmits and the third rotation support shaft 432. And have.

The second cam 431 has a shape in which a part of the outer peripheral surface of a cylindrical column having a hollow inside is cut out, and the third rotation support shaft 432 is inserted through the center of the second rotation support shaft 432. The shaft 432 is slidably supported along the X-axis direction.
Further, an engagement protrusion 431a protruding outward is provided on the outer peripheral surface of the second cam 431, and the elongated hole 423c formed along the longitudinal direction on the one end side of the swing arm 423 described above is provided. Has been inserted. Thus, when the swing arm 423 swings by the rotation of the first cam 421, the second cam 431 moves along the X-axis direction. In addition, the code | symbol 435 shown in FIG. 8 is a detent | locking of the 2nd cam 431 in which the long hole 435a along the X-axis direction was formed. When the engagement protrusion 431a is inserted through the elongated hole 435a, the movement of the engagement protrusion 431a in the Y-axis direction is restricted, and the rotation of the second cam 431 is restricted.
The second cam 431 has an elongated hole 431b formed along the X-axis direction on the outer peripheral surface thereof, and the distal end portion of the follower protrusion 433 is inserted into the elongated hole 431b. The elongated hole 431b has a substantially spiral section in the middle of the slot 431b, the second cam 431 slides along the third rotation support shaft 432, and the follower protrusion 433 has a substantially spiral section. When this happens, the follower projection 433 moves along the circumferential direction, thereby enabling the third rotation support shaft 432 to rotate.

  The link member 434 is supported by the third rotation support shaft 432 and rotates together with the third rotation support shaft 432. Further, the link member 434 is generally disposed in a state in which the link member 434 is directed in the Z-axis direction, and a rotating end portion thereof is connected to a power transmission arm 206 extending from the second frame body 201. Therefore, when the third rotation support shaft 432 and the link member 434 are rotated by the direct movement of the second cam 431, a moving force along the Y-axis direction is applied to the power transmission arm 206, and the second frame 201 and The first frame 101 is moved in the Y-axis direction.

(Positioning mechanism: Operation explanation)
Next, the movement state which each cam 421,431 gives with respect to the follower by the switching of five steps by the movement operation lever 441 is demonstrated based on FIG.
(1) The state in which the movement operation lever 441 is set to the position where the engagement protrusion of the leaf spring 417 is fitted in the engagement recess 412 is defined as the first state. At this time, the protrusion 423a is at the first position in FIG. 10A, which is one end side of the cam groove 421a of the first cam 421, and the first frame body 101 is located on the rightmost side. The follower protrusion 433 is at the first position in FIG. 10B, which is one end of the elongated hole 431b of the second cam 431, and the second frame body 201 is positioned at the rearmost side. With these arrangements of the first and second frames 101 and 201, the threading shaft 11 is in a position where the threading hook 20 performs threading on the sewing needle 1.
(2) A state in which the movement operation lever 441 is set to a position where the engagement protrusion of the leaf spring 417 is fitted in the engagement recess 413 is a second state. At this time, the protrusion 423a is at the second position in FIG. 9A of the cam groove 421a of the first cam 421, and the first frame body 101 moves to the left. The follower projection 433 is at the second position in FIG. 9B of the elongated hole 431b of the second cam 431, and the second frame body 201 does not move from the state of (1). The moving distance of the first frame 101 at this time coincides with the distance in the X-axis direction between the sewing needle 1 and the sewing needle 2, and the arrangement of the first and second frames 101 and 201 causes the threading shaft 11 to be threaded. The threading hook 20 is positioned to thread the sewing needle 2.
(3) A state in which the movement operation lever 441 is set to a position where the engagement protrusion of the leaf spring 417 is fitted in the engagement recess 414 is defined as a third state. At this time, the protrusion 423a is at the third position in FIG. 9A of the cam groove 421a of the first cam 421, and the first frame body 101 moves to the left. Further, the follower protrusion 433 is at the third position in FIG. 9B of the elongated hole 431b of the second cam 431, and the second frame body 201 moves to the front side. At this time, the moving distance of the first frame 101 coincides with the interval between the sewing needle 2 and the sewing needle 3 in the X-axis direction, and the moving distance of the second frame 201 is the Y-axis direction between the sewing needle 2 and the sewing needle 3. Match the interval. Therefore, by the arrangement of the first and second frame bodies 101 and 201, the threading shaft 11 is in a position where the threading hook 20 performs threading on the sewing needle 3.
(4) A state in which the movement operation lever 441 is set to a position where the engagement protrusion of the leaf spring 417 is fitted in the engagement recess 415 is defined as a fourth state. At this time, the protrusion 423a is at the fourth position in FIG. 9A of the cam groove 421a of the first cam 421, and the first frame body 101 moves to the left. The follower protrusion 433 is located at the fourth position in FIG. 9B of the elongated hole 431b of the second cam 431, and the second frame body 201 does not move from the state of (3). At this time, the moving distance of the first frame 101 coincides with the interval between the sewing needle 3 and the sewing needle 4 in the X-axis direction, and the arrangement of the first and second frames 101 and 201 causes the threading shaft 11 to be threaded. The threading hook 20 is positioned to thread the sewing needle 4.
(5) A state in which the movement operation lever 441 is set to a position where the engagement protrusion of the leaf spring 417 is fitted in the engagement recess 416 is defined as a fifth state. At this time, the protrusion 423a is at the fifth position in FIG. 9A of the cam groove 421a of the first cam 421, and the first frame body 101 moves to the left. The follower protrusion 433 is at the fifth position in FIG. 9B of the elongated hole 431b of the second cam 431, and the second frame body 201 does not move from the state of (3). The moving distance of the first frame 101 at this time coincides with the distance between the sewing needle 4 and the sewing needle 5 in the X-axis direction, and the arrangement of the first and second frames 101 and 201 causes the threading shaft 11 to be threaded. The threading hook 20 is positioned to thread the sewing needle 5.
As shown in the above (1) to (5), by performing the position switching operation of the movement operation lever 441 in order from the first state to the fifth state, the threading hook 20 is placed at each position of the sewing needles 1 to 5. The threading shaft 11 is positioned at a position where threading is possible, and threading can be performed for each of them.

(Threading operation input mechanism: overall configuration)
The threading operation input mechanism 300 will be described with reference to FIGS. FIG. 11 is a perspective view of the threading operation input mechanism 300, and FIG. 12 is an explanatory view of the main part of the threading cam mechanism 340.
The threading operation input mechanism 300 has an operation lever 310 as a threading operation input means for inputting a threading operation by moving the threading shaft 11 downward, and a threading shaft by an input operation from the operation lever 310 downward. 11, a threading slide guide 320 as a lifting member that performs a lowering operation together with the needle 11, and a height adjusting mechanism that stops the threading shaft 11 that descends at a plurality of heights corresponding to the height of the eye holes of the sewing needles 1 to 5. 330 and a threading cam mechanism 340 that rotates the threading shaft 11 in a direction in which the threading hook 20 moves forward when only the threading slide guide 320 moves downward relative to the threading shaft 11.

(Threading operation input mechanism: threading slide guide)
The threading slide guide 320 is vertically long and has a plate-like support which is provided integrally with a back plate 321 having an arcuate cross section and both upper and lower ends thereof and through which the threading shaft 11 is inserted. 322 and 323, and an engagement shaft 324 with the operation lever 310 extending leftward from the back plate 321 along the X-axis direction.
Each of the support portions 322 and 323 has a plate shape along the XY plane and is formed with a through hole through which the threading shaft 11 is inserted. The threading slide guide 320 is threaded through the through hole. The threading shaft 11 is slidably connected along the threading shaft 11. A compression coil spring 325 is interposed between the upper support portion 322 and a first guide pin 331 provided on a threading shaft, which will be described later, and a support portion 322 is provided at the upper end portion of the threading shaft 11. Since the stopper 11a that is in contact with the upper surface is provided, between the threading shaft 11 and the threading slide guide 320, the threading shaft 11 is pressed downward and the threading slide guide 320 is pressed upward. So that it is constantly energized.

(Threading operation input mechanism: control lever)
As shown in FIGS. 3 and 11, the operation lever 310 is supported by a plate-like bracket along a YZ plane (not shown) that protrudes from the front frame 92 of the main frame 90 toward the front. The upper and lower slots 311 are inserted through the two guide shafts that are provided to project leftward from the bracket, and are held so as not to drop off by the C-rings provided at the distal ends of the guide shafts. The operation lever 310 is supported by the structure so as to be movable up and down with respect to the main frame 90.
The operation lever 310 includes a long main body 312 extending in the vertical direction, and an arm 313 extending in the direction (Y-axis direction) perpendicular to the main body 312 near the middle of the main body 312. , And a box-like portion 314 provided at the lower portion of the main body portion 312.
The main body 312 and the box-shaped portion 314 are integrally connected, and the lower end of the box-shaped portion 314 is bent at a right angle to form an input portion 315 extending along the X-axis direction. A downward pressing operation is input. Further, the box-shaped portion 314 is connected to the main frame 90 by a tension spring 316, and the upward pulling force is always urged.
On the other hand, a long groove 317 is formed through the arm portion 313 along the Y-axis direction, and an engagement shaft 324 extending from the threading slide guide 320 is inserted therein. Accordingly, the downward movement operation input to the operation lever 310 is transmitted from the arm portion 313 to the threading slide guide 320 and the threading shaft 11 via the engagement shaft 324. Further, upward tension by the tension spring 316 extends from the box-shaped portion 314 to the threading slide guide 320 and the threading shaft 11 via the main body 312. The long hole 317 of the arm portion 313 is along the Y-axis direction in order to allow the second support mechanism 200 to move in the Y-axis direction.

(Threading operation input mechanism: threading cam mechanism)
As shown in FIG. 12, the threading cam mechanism 340 includes an engagement protrusion 341 that protrudes in the horizontal direction from the threading shaft 11 toward the back plate 321 of the threading slide guide 320, and the back plate of the threading slide guide 320. 321 and a slot 342 formed as a groove cam.
The engagement protrusion 341 is actually a rear end portion of a first guide pin 331 (described later) that is provided to penetrate the threading shaft 11. The engagement protrusion 341 is inserted into a long hole portion 342 penetratingly formed in the back plate 321 and is set to a length that penetrates to the outside of the back plate 321.
The long hole portion 342 is formed such that its longitudinal direction is inclined with respect to the vertical direction. The engagement protrusion 341 is normally maintained at the lower end portion of the elongated hole portion 342 by the action of the compression coil spring 325 provided between the threading shaft 11 and the threading slide guide 320. The elongated hole portion 342 is inclined in a direction in which displacement occurs in the direction in which the threading shaft 11 rotates in the direction in which the threading hook 20 advances when the engaging protrusion 341 moves up along the elongated hole portion 342. ing. That is, the threading shaft 11 rotates clockwise in a plan view so that the threading hook 20 moves forward, so that the elongated hole portion 342 is inclined in the direction toward the back side in the Y-axis direction as it goes upward. Yes.
The engagement protrusion 341 moves upward along the elongated hole portion 342 when the threading slide guide 320 is lowered relative to the threading shaft 11. As described above, the threading shaft 11 and the threading slide guide 320 are operated by the action of the compression coil spring 325 provided between the threading shaft 11 and the threading slide guide 320 and the stopper 11a at the upper end of the threading shaft 11. And move up and down together unless a force greater than the pressing force of the compression coil spring 325 is applied. Accordingly, a height adjusting mechanism 330 that prevents the lowering of the threading shaft 11 is provided in the middle of the lowering path. When a lowering operation is input to the threading slide guide 320 and the threading shaft 11 by the operation lever 310, Only the threading shaft 11 is prevented from descending on the way. At this time, when a pressing force larger than that of the compression coil spring 325 is input from the operation lever 310, the threading slide guide 320 is lowered relative to the threading shaft 11, and the threading shaft 11 is operated by the operation of the threading cam mechanism 340. Rotates, and the threading hook 20 moves forward to perform threading. The retraction of the threading hook 20 is performed by the return force of the compression coil spring 325 by releasing the operation lever 310.

(Threading operation input mechanism: height adjustment mechanism)
The height adjusting mechanism 330 has a function of preventing only the threading shaft 11 from being lowered at a predetermined height when the slide guide 320 is lowered in order to operate the threading cam mechanism 340, and threading of the sewing needles 1 to 5. It sometimes has a function of adjusting the height of the threading hook 20 for each of the sewing needles 1 to 5 in cooperation with the positioning mechanism 400 that moves and positions the threading shaft 11 according to the arrangement of the sewing needles.
That is, the height adjusting mechanism 330 includes first and second guide pins 331 and 332 provided on the threading shaft 11 and five contact portions 351 to 351 on which one of the guide pins 331 and 332 contacts from above. And a lower threading guide 350 provided with 355 and an upper threading guide 360 (not shown in FIG. 11) for guiding the circular movement of the guide pins 331 and 332 when the threading shaft 11 is rotated.

  The first and second guide pins 331 and 332 are both provided perpendicular to the threading shaft 11, and the first guide pin 331 is disposed upward. The two guide pins 331 and 332 are arranged on the threading shaft 11 at different angles with the threading shaft 11 as the center on the XY plane.

FIG. 13 is a perspective view of the lower threading guide 350, and FIG. 14 is in contact with the guide pins 331 and 332 when the threading shaft 11 is positioned in an arrangement corresponding to the sewing needles 1 to 5 by the positioning mechanism 400. It is explanatory drawing which shows the relationship with the parts 351-355.
The lower threading guide 350 is a block-like member that is fixedly supported by the needle bar 6 and includes five contact portions 351 to 355 on the upper portion.
As shown in FIG. 14 (A), the contact portion 351 is arranged so that the first guide pin 331 descends and contacts when the threading shaft 11 is positioned at a position where the threading shaft 11 is threaded. As shown in FIG. 14 (B), the contact portion 352 is arranged so that the first guide pin 331 descends and contacts when the threading shaft 11 is positioned at a position where the threading shaft 11 is threaded. As shown in FIG. 14C, the contact portion 353 is arranged so that the second guide pin 332 is lowered and contacts when the threading shaft 11 is positioned at a position where the threading shaft 11 is threaded. As shown in FIG. 14 (D), the contact portion 354 is arranged so that the second guide pin 332 is lowered and contacts when the threading shaft 11 is positioned at a position where the threading needle 11 is threaded. As shown in FIG. 14 (E), the threading shaft 11 is sewn on the contact portion 355. 5 second guide pin 332 is in place abutting lowered when it is positioned in the position for threading into.
In addition, the flat surfaces of the contact portions 351 to 355 are formed in a substantially arc shape so that the guide pins 331 and 332 can maintain the contact state when the threading shaft 11 contacts and rotates. Has been.
Further, each of the contact portions 351 to 355 determines the height of the threading shaft 11 and the threading hook 20 at the time of threading. The height is set differently depending on the height of the eye hole.
Further, the contact portions 351, 352 and the contact portions 353, 354, 355 are arranged in accordance with the opening angles of the guide pins 331, 332 around the threading shaft 11 respectively. In this manner, a plurality of contact portions are distributed according to the number of guide pins, and interference with the placement of each contact portion is avoided.
In addition, there are two guide pins 331 and 332. When one of the guide pins 331 and 332 comes into contact with the contact portion, the other guide pin 331 and 332 are connected to the first guide pin 331 so that the other does not contact any of the contact portions. A difference in height is provided from the second guide pin 332. In addition, when one guide pin is in contact with the contact portion, the escape portion 356 is formed to be partly lower from the upper surface so that the other guide pin does not contact any portion other than the contact portion of the lower threading guide 350. Is formed (see FIG. 14A).
Since the lower threading guide 350 has a function of determining the height of the threading hook 20 during threading, the lower threading guide 350 is always required to have a certain height. Accordingly, the sewing machine motor is controlled so that the upper shaft angle of a predetermined section is set so that the needle bar is always in the same threading-capable section during threading.

FIG. 15 is an enlarged perspective view of the lower threading guide 350 and the upper threading guide 360.
The upper threading guide 360 is configured so that any one of the guide pins 331 and 332 that are in contact with the respective contact portions 351 to 355 of the lower threading guide 350 causes the upper surfaces of the contact portions 351 to 355 to be rotated by the rotation of the threading shaft 11. It has a function of guiding the guide pin by abutting from above so as to maintain the abutment when moving.
Accordingly, as shown in FIG. 15, the upper threading guide 360 is a guide part that abuts and guides when the first guide pin 331 moves in contact with the contact part 351 of the lower threading guide 350. 361, when the first guide pin 331 contacts and moves with the contact portion 352, and when the second guide pin 332 contacts and moves with the contact portion 353. A guide portion 363 that contacts and guides the second guide pin 332 when the second guide pin 332 contacts and moves to the contact portion 354, and a second guide pin that contacts the contact portion 355. A guide portion 365 that abuts and guides when the 332 abuts and moves, a relief portion 366 that allows the first guide pin 331 to descend when the threading shaft 11 descends, and a first portion when the threading shaft 11 descends. Second guide pin 3 And a relief portion 367 that allows the second descent.

(Clamping part)
16A is a perspective view of the yarn holding mechanism 50, and FIG. 16B is a cross-sectional view taken along the line VV in FIG. 16A.
The yarn holding mechanism 50 is made of a member formed by bending a sheet metal, and as shown in FIG. 16, two yarn hooking portions 51 and 52 for hooking the yarn at the lower end portion, and a plate for holding the yarn end portion And a holding portion 53 having a spring. The two thread hooking portions 51 and 52 each have a notch for hooking a sewing thread, and the sewing thread can be passed over these to pass the sewing thread in the X-axis direction.

The sandwiching portion 53 includes a main body plate 55 as a sandwiching member formed integrally with the yarn hooking portions 51 and 52, a rotating plate 56 as a sandwiching member rotatable with respect to the main body plate 55, and A support pin 57 that rotatably supports the rotation plate 56 and a pressing spring 58 that is a first elastic member that urges the rotation plate 56 toward the main body plate 55 are provided. Both the main body plate 55 and the rotating plate 56 are extended with their tip portions directed downward, and the rotating plate 56 rotates the lower end portion so as to sandwich the sewing thread.
The support pin 57 is erected on the back side of the main body plate 55 along the Y-axis direction, the rotation plate 56 has a through hole, and the support pin 57 is loosely inserted. The rotation plate 56 has a clearance with respect to the support pin 57 by setting the inner diameter of the through hole larger than that of the support pin, and the rotation with respect to the main body plate 55 is enabled by the clearance.

Further, the body plate 55 has side wall portions 55a bent along the YZ plane at both left and right end portions thereof. These side wall portions 55a are all located above the lower end portion of the main body plate 55 and are raised to the rotating plate 56 side. Thereby, the rotation of the rotation plate 56 around the support pin 57 is prevented. Further, each side wall 55 a has a lower end set lower than the support pin 57. Thus, when the sewing thread is sandwiched from below, the lower end portion of the side wall portion 55a serves as a stopper that prevents the sewing thread from entering further upward.
It is desirable that the rotating plate 56 is supported so that the lower portion of the clamping portion 53 is opened, and the sewing thread is quickly released by its own weight when the rotating plate 56 is opened. Therefore, it is possible to prevent the sewing thread from entering too far into the back by the side wall portions 55a, and it is possible to satisfactorily perform the thread lowering.

  Further, the main body plate 55 is formed with a window portion 55b formed through the front and back. The window portion 55b is provided at a position where the sewing thread at the position locked by the pair of side wall plates 55a can be seen. The window portion may be provided on the rotating plate 56 side as long as the clamped sewing thread is visible, or may be provided on both the main body plate 55 and the rotating plate 56. Further, as in the window portion 55b described above, it is desirable that the clamped sewing thread be provided at a position and a direction that can be observed from the position where the operator can work with respect to the sewing machine.

As described above, the clamping portion 53 is adjacent to the direction in which the two thread hooks 51 and 52 are arranged, and the remainder of the sewing thread when threading is performed in a state where the two thread hooks 51 and 52 are crossed. By holding the end portion between the holding portions 53, it is possible to maintain a state where the sewing thread is stretched along the X-axis direction between the two thread hook portions 51 and 52.
By arranging the thread holding mechanism 50 on the opposite side of the threading hook 20 with the sewing thread stretched along the X-axis direction in this manner, the threading moved forward along the Y-axis direction. When the hook 20 passes right above the orthogonal sewing thread, the sewing thread can be captured smoothly by returning when the hook 20 moves backward.

(Thread holding mechanism support mechanism)
17 is a front view of the yarn holding mechanism 50 and the yarn holding mechanism support mechanism 60, and FIGS. 18 to 20 are perspective views sequentially showing the operations of the yarn holding mechanism 50 and the yarn holding mechanism support mechanism 60 accompanying the threading operation. . FIG. 17 shows the posture when the yarn holding mechanism 50 is at the threading position, and when the yarn holding mechanism 50 is at the standby position, it is slightly inclined clockwise around the Y axis as shown by the solid line in FIG.
The yarn holding mechanism support mechanism 60 is fixedly supported on the front side of the first frame 101 and the movable body 61 that supports the yarn holding mechanism 50 so as to be rotatable about the X axis on the front side of the first frame 101. And a cam plate 62 that supports the movable body 61 so that the movable body 61 can be moved up and down and pivoted about the Y axis, and a rotation operation imparting mechanism 63 that imparts rotation of the thread holding mechanism 50 at the lower end of the movable body 61. I have.

  The cam plate 62 is held by the first frame 101 in a state along the XZ plane, and first and second cam grooves 62a and 62b along the vertical direction are formed through the front and back. The first cam groove 62a is formed straight along the Z-axis direction. The second cam groove 62b is adjacent to the left side of the first cam groove 62a, the upper end portion and the lower end portion are both formed along the Z-axis direction, and the middle section is such that the lower end portion approaches the right side. It is partly bent and formed.

The movable body 61 has an upper end portion connected to a stopper 11a provided at the upper end portion of the threading shaft 11, and a first follower protrusion 61a that slides along the first cam groove 62a on the upper end portion. I have. Further, a second follower protrusion 61b that slides along the second cam groove 62b is provided in the vicinity of the upper end portion of the moving body 61 and below the first follower protrusion 61a. Since the movable body 61 is connected to the threading shaft 11 by the stopper 11a, when the operation lever 310 is pushed down during execution of the threading operation, the moving body 61 is lowered together with the threading shaft 11 and at the lower stop position of the threading shaft. Both are supposed to stop.
As described above, since the second cam groove 62b is bent to the right in the middle, the lower part of the moving body 61 moves to the right during the downward movement. As a result, the second cam groove 62b is bent about the Y axis. Rotate clockwise. At that time, the sewing thread over the two thread hooks 51 and 52 is set so as to face the threading hook 20 that advances.
Furthermore, the moving body 61 is a member formed by bending a sheet metal, and its upper half is along the XZ plane, bent from the middle, and its lower half is almost along the YZ plane. Is arranged. And the thread | yarn holding | maintenance mechanism 50 is pivotally supported by the support shaft provided in the lower end part of the said lower half perpendicularly | vertically to the plate surface so that rotation to the X-axis rotation is possible. The lowermost end portion is provided with a stopper 61c protruding substantially along the XY plane, and abuts when the yarn holding mechanism 50 rotates to determine the position of the yarn holding mechanism 50.

  The rotating motion imparting mechanism 63 includes a swing link body 64 that is rotatably supported around the X axis at the upper end portion of the lower half along the YZ plane of the moving body 61, and a main body plate 55 of the yarn holding mechanism 50. Are provided on the back plate 321 of the threading slide guide 320 and the swinging link body 64 is swung. And an engaging protrusion 66.

  The swing link body 64 extends along the vertical direction, and is supported by the moving body 61 at its upper end. And the pin 64a along the X-axis direction is fixedly equipped in the lower end part. On the other hand, the driven arm portion 65 is formed with a long hole along the Z-axis direction into which the pin 64a is inserted. When the swing link body 64 rotates counterclockwise in FIG. Thus, the main body plate 55 can be rotated clockwise. The main body plate 55 is rotated clockwise so that the sewing thread stretched over the thread hooks 51 and 52 can be moved toward the sewing needles 1 to 5.

In addition, a contact protrusion 64 b that contacts the engagement protrusion 66 provided on the threading slide guide 320 from below is provided on the upper end portion of the swing link body 64. The relative arrangement of the engagement protrusions 66 and the contact protrusions 64b is such that the movable body 61 is vertically aligned in a state where the movable body 61 is rotated counterclockwise by the cam grooves 62a and 62b of the cam plate 62. ing.
The threading slide guide 320 descends together with the threading shaft 11 when a threading operation is input, and the guide pin 331 or 332 comes into contact with the lower threading guide 350 and only the threading shaft 11 is prevented from descending. Only the threading slide guide 320 is further lowered, but at that time, the threading against the contact protrusion 64b of the swinging link body 64 supported by the moving body 61 that is completely interlocked with the threading shaft 11 is performed. The engaging protrusion 66 provided on the through slide guide 320 relatively moves downward. Then, as shown in FIG. 20, the engagement protrusion 66 contacts and presses against the contact protrusion 64b from above. At this time, the contact protrusion 64b is provided at a position shifted in the Y-axis direction (back surface side) with respect to the support shaft of the swing link body 64, so that the lower end portion of the swing link body 64 is in the reverse direction ( It will be rotated to the surface side.
On the other hand, as described above, since the driven arm portion 65 is connected to the pin 64a at the lower end portion of the swing link body 64 by the elongated hole, the swing arm portion 65 is turned toward the surface side, The main body plate 55 on the opposite side is rotated to the back side through the swing arm 65 and the support shaft. Therefore, the sewing thread stretched over the thread hooks 51 and 52 is brought closer to the sewing needles 1 to 5 side.

(Thread release mechanism)
FIG. 21 is a perspective view showing the entire yarn release mechanism 70, FIG. 22 is a diagram for explaining the principle of the yarn release mechanism, and FIGS. 23A to 23D are diagrams for explaining the operation of the yarn release mechanism.
The yarn release mechanism 70 includes a contact portion 71 integrally provided at the upper end portion of the rotation plate 56 of the above-described yarn holding mechanism 50, and a first portion that contacts the contact portion 71 and rotates the rotation plate 56. 2 and a thread release plate 72 which is an elastic member.
The contact portion 71 is bent at the upper end of the rotation plate 56 perpendicularly to the plate surface of the rotation plate 56 and extends in the Y-axis direction (back surface side).
The thread release plate 72 is fixed to the lower end portion of the threading slide guide 320 with a screw so as to extend from the threading slide guide 320 toward the surface side in the Y-axis direction. The extended tip of the yarn release plate 72 is set to a length that comes into contact with the tip of the contact portion 71 when the threading slide guide 320 moves up and down.
The relative height relationship between the thread release plate 72 and the contact portion 71 is determined when the threading shaft 11 is prevented from descending and only the threading slide guide 320 starts to descend when the threading operation is descending. In this case, the thread release plate 72 is positioned above the contact portion 71, and the thread release plate 72 is positioned below the contact portion 71 when reaching the lowest lowered position of the threading slide guide 320. ing.
In such a structure, in the thread releasing mechanism 70, the threading slide guide 320 and the threading shaft 11 are simultaneously lowered during the threading operation, and only the threading slide guide 320 continues to be lowered from the middle. When the yarn release plate 72 comes into contact with and urges the contact portion 71 from above, the yarn release plate 72 bends over the entire length of the extension length L1 (FIG. 23A). At this time, the moment that the thread release plate 72 exerts on the rotating plate 56 with the refracting portion 55a of the main body plate 55 as a fulcrum is much smaller than the moment that the pressing spring 58 exerts on the rotating plate 56. The spring constant of the pressing spring 58 and various dimensions of the main body plate 55, the rotation plate 56, and the thread release plate 72 are set. For this reason, even if the thread release plate 72 urges the contact portion, the thread release plate 72 remains in contact with the main body plate 55 and continues to hold the sewing thread.
The yarn release plate 72 bends upward to avoid the contact portion 71 and reach below the contact portion 71 (FIG. 23B). At that time, the threading shaft 11 is rotated by the action of the threading cam mechanism 340, and the threading hook 20 moves forward to pass through the eye holes of a predetermined sewing needle to capture the sewing thread held by the thread holding mechanism 50. To do. The entire yarn holding mechanism 50 is tilted somewhat clockwise by the action of the yarn holding mechanism support mechanism 60. However, in FIG. 23B, the yarn holding mechanism 50 is not shown in a tilted state in order to simplify the explanation of the operation. . Even when the yarn holding mechanism 50 is tilted, the tip of the yarn release plate 72 is set to a length that can reach the contact portion 71.
Subsequently, when the threading slide guide 320 starts to rise from the bottom dead center, the threading shaft 11 is rotated in the reverse direction by the action of the threading cam mechanism 340, and the threading hook 20 is retracted and the stitches of the sewing needles are rotated. The sewing thread is pulled into the eye hole. At that time, the thread release plate 72 contacts the contact portion 71 from below. At this time, the thread releasing plate 72 and the pressing plate 58 are pressed so that the moment that the thread releasing plate 72 exerts on the rotating plate 56 with respect to the refracting portion 55a of the main body plate 55 is larger than the moment that the pressing spring 58 exerts on the rotating plate 56. The spring constant of the spring 58 and various dimensions of the main body plate 55, the rotation plate 56, the thread release plate 72, and the thread release restriction plate 73 are set. For this reason, when the thread release plate 72 urges the contact portion 71, the rotating plate 56 integrally formed with the contact portion 71 rotates clockwise with the refracting portion 55a as a fulcrum, and moves away from the main body plate 55 to the thread. Release is performed. (FIG. 23C) The thread release plate 72 rotates and pushes the contact portion 71 and reaches above the contact portion 71. (FIG. 23D).

(Explanation of threading device operation)
The threading operation of the threading device 10 having the above configuration will be described.
First, the sewing needles 1 to 5 for threading are selected by rotating the movement operation lever 441.
At this time, the first cam mechanism 420 moves the first frame 101 of the first support mechanism 100 in the X-axis direction according to the angular position of the movement operation lever 441, and the second cam mechanism 430 The second frame 201 of the support mechanism 200 is moved in the Y-axis direction. The threading shaft 11 is moved and positioned at a predetermined position in the XY plane by these cooperation.
At this time, the height adjustment mechanism 330 determines which guide pins 331 and 332 are in contact with which of the contact portions 351 to 355.
When the operation lever 310 is operated downward, the threading shaft 11 starts to move down together with the threading slide guide 320. Further, the movable body 61 is pressed downward by the stopper 11a at the upper end of the threading shaft 11, and the thread holding mechanism 50 also starts to descend.
When the predetermined guide pins 331 and 332 extending from the threading shaft 11 come into contact with the predetermined contact portions 351 to 355, the lowering operation is prevented, and the threading is performed according to the set height of the contact portion. The shaft 11 and threading hook 20 are adjusted to the height of the selected sewing needle. Further, the thread holding mechanism 50 interlocked by the moving body 61 is similarly adjusted to the height of the selected sewing needle.
When the operation lever 310 is further pushed downward from this point, only the threading slide guide 320 moves downward with respect to the threading shaft 11, and the threading shaft 11 rotates clockwise by the action of the threading cam mechanism 340. . Further, the rotation operation applying mechanism 63 rotates the yarn holding mechanism 50 to a position where it contacts the stopper 61c. As a result, the threading hook 20 moves forward and penetrates a predetermined hole of the sewing needle, and the thread holding mechanism 50 tilts toward the sewing needle side and applies the sewing thread stretched in the X-axis direction to the front of the threading hook 20. The return of the threading hook 20 catches the sewing thread. At this time, the thread release plate 72 located at the lower end of the threading slide guide 320 contacts the contact part 71 from above and bends upward, and moves to the lower side of the contact part 71.
When the operation lever 310 is released from the downward pressing state, only the threading slide guide 320 starts to move upward relative to the threading shaft 11 and the threading hook 20 starts to move backward. Threading is executed by drawing the captured sewing thread into the eye hole of the sewing needle. When the threading slide guide 320 starts to rise from the bottom dead center , the thread release plate 72 comes into contact with the contact portion 71 from below to rotate the contact portion 71 and the rotation plate 56, and the clamping portion 53 Open and release the thread. Accordingly, the sewing thread is smoothly drawn into the eye holes of the sewing needle.
Further, when threading another sewing needle, the moving operation lever 441 is rotated again and the operation lever 310 is operated downward.

(Effect of threading device)
In the threading device 10, the first support mechanism 100 and the second support mechanism 200 support the threading shaft 11 so as to be movable to an arbitrary position in the XY plane, and the positioning mechanism 400 includes two cam mechanisms 420. , 430 are selectively moved and positioned at five locations corresponding to the sewing needles 1 to 5 in accordance with the rotation operation of the movement operation lever 441.
Therefore, even if the sewing machine is equipped with five sewing needles 1 to 5 like a sewing machine that can realize sewing of overlock and cover stitch by one machine, these are not simple arrangements such as one row. The threading shaft 11 can be positioned only by rotating the moving operation lever 441 without requiring input of individual position adjustment operations in a plurality of directions, and all the sewing needles 1 to 5 are sequentially arranged. Alignment can also be performed. Accordingly, it is possible to perform proper threading with respect to all the sewing needles 1 to 5.
In addition, since the first frame 101 is equipped with the thread holding mechanism 50 via the moving body 61, not only the threading shaft 11 but also the thread holding mechanism 50 can be operated only by rotating the movement operation lever 441. Positioning can be performed in order for all the sewing needles 1 to 5 in the direction, and further, proper threading can be performed for all the sewing needles 1 to 5.

Further, in the threading device 10, the heights of the contact portions 351 to 355 of the lower threading guide 350 of the threading operation input mechanism 300 are set corresponding to the sewing needles 1 to 5, respectively. The threading hook 20 can be adjusted to an appropriate height with respect to the eye holes of the sewing needles 1 to 5.
And even if it is a case where five sewing needles 1 to 5 are mounted like a sewing machine that can realize sewing of overlock and cover stitch with a single machine, it has two guide pins 331 and 332. Therefore, the contact portions 351 to 355 can be dispersed and provided on the lower threading guide 350, the height of the threading hook 20 can be adjusted appropriately, and further threading optimization can be achieved. Is possible.

Further, the threading device 10 releases the sewing thread held by the thread holding mechanism 50 when the thread releasing mechanism 70 starts to rise from the bottom dead center . That is, since the sewing thread is held when the thread holding mechanism 50 is lowered or when the threading hook is advanced, it is possible to avoid a situation in which the sewing thread deviates from the capture position and causes a threading defect. Therefore, it is possible to perform threading properly and increase the reliability of the mechanism.

  Further, the thread release mechanism 70 releases the sewing thread by coming into contact with the clamping portion 53 when the thread release member 72 provided at the lower end of the threading slide guide 320 moves downward, so that the operation transmission mechanism for releasing the thread is used. Simplification can be achieved, and it is possible to reduce the cost and malfunction of the apparatus.

  Further, since the window portion 55b is provided so that the sewing thread clamped by the main body plate 55 of the clamping section 53 of the thread holding mechanism 50 can be visually confirmed, the sewing thread holding state can be visually confirmed, and the thread caused by unintentional dropping of the sewing thread or the like. It is possible to suppress the occurrence of threading defects.

(Second embodiment of the thread release mechanism)
A second embodiment of the yarn release mechanism will be described.
The thread release mechanism 70A is an example in which a second elastic member is provided on the rotating plate 56.
24 is a perspective view showing the whole of the yarn release mechanism 70A, FIG. 25 is a diagram for explaining the principle of the yarn release mechanism A, and FIGS. 26A to 26D are diagrams for explaining the operation of the yarn release mechanism 70A.
The yarn release mechanism 70A includes an engagement member 75 provided at the lower end of the elevating member 320, a bent portion 76 provided integrally with the upper end portion of the rotating plate 56 of the yarn holding mechanism 50, and an engagement portion. And an elastic member 77 that is a second elastic member that contacts the 75 and rotates the rotation plate 56.
The bent portion 76 is bent at the upper end portion of the rotating plate 56 perpendicularly to the plate surface of the rotating plate 56, and extends in the Y-axis direction (back surface side).
The elastic member 77 is screwed to the bent portion 76 so as to extend toward the back side in the Y-axis direction. The engaging member 75 is fixed to the lower end portion of the threading slide guide 320 with a screw so as to extend from the threading slide guide 320 toward the surface side in the Y-axis direction. The extended tip of the engaging member 75 is set to a length that contacts the tip of the elastic member 77 when the threading slide guide 320 moves up and down.
In addition, the relative height relationship between the engaging member 75 and the elastic member 77 is such that when the threading shaft 11 is stopped from descending and only the threading slide guide 320 starts to descend when the threading operation is descending. When the engaging portion 75 is positioned above the elastic member 77 and reaches the lowest lowered position of the threading slide guide 320, the engaging portion 75 is set to be positioned below the second elastic member 77. ing.
In such a structure, in the thread release mechanism 70A, when the threading slide guide 320 and the threading shaft 11 are simultaneously lowered during the threading operation, and only the threading slide guide 320 continues to be lowered halfway, the engaging portion 75 is moved upward. To contact and bias the elastic member 77. (FIG. 26 (A)). At this time, the moment that the engaging portion 75 exerts on the rotating plate 56 and the refracted portion 55a of the main body plate 55 serves as a fulcrum is pressed against the elastic member 77 so that the moment that the pressing spring 58 exerts on the rotating plate 56 is extremely small. The spring constant of the spring 58 and various dimensions of the main body plate 55, the rotating plate 56, the elastic member 77, and the engaging portion 75 are set. For this reason, even when the engaging portion 75 urges the elastic member 77, the thread release plate 72 maintains the posture in contact with the main body plate 55 and continues to hold the sewing thread.
Then, the engaging member 75 avoids the second elastic member 77 and reaches below the elastic member 77 as the elastic member 77 bends downward (FIG. 26B). At that time, the threading shaft 11 is rotated by the action of the threading cam mechanism 340, and the threading hook 20 moves forward to pass through the eye holes of a predetermined sewing needle, and the sewing thread held by the thread holding mechanism 50 is removed. To capture. The entire yarn holding mechanism 50 is tilted somewhat clockwise by the action of the yarn holding mechanism support mechanism 60. However, in FIG. 26B, the yarn holding mechanism 50 is not shown in a tilted state in order to simplify the operation description. . Even when the thread holding mechanism 50 is tilted, the engagement member 75 is set to a length that can reach the second elastic member 77.
Subsequently, when the threading slide guide 320 starts to rise from the lower fulcrum, the threading shaft 11 is rotated in the reverse direction by the action of the threading cam mechanism 340, and the threading hook 20 is retracted and the stitches of the sewing needle are inserted. The sewing thread is pulled into the eye hole. At that time, the engaging member 75 comes into contact with the elastic member 77 from below. At this time, the elastic member 77 and the pressing member 58 are pressed so that the moment that the engaging member 75 exerts on the rotating plate 56 is larger than the moment that the pressing spring 58 exerts on the rotating plate 56. The spring constant of the spring 58 and various dimensions of the main body plate 55, the rotating plate 56, the bent portion 76, and the engaging member 75 are set. For this reason, when the engaging member 75 urges the elastic member 77, the rotating plate 56 integrally formed with the bent portion 76 rotates clockwise with the refracting portion 55a as a fulcrum, and the yarn is released from the main body plate 55. Done. (FIG. 26C) The engaging member 75 rotates and pushes the rotating plate 56, and reaches above the second elastic member 77. (FIG. 26D).

(Third embodiment of the thread release mechanism)
A third embodiment of the yarn release mechanism will be described.
This yarn release mechanism 70 is obtained by adding a regulating member 73 to the yarn release mechanism 70 to reduce the amount of bending of the second elastic member.
FIG. 27 is a perspective view showing the entire yarn release mechanism 70B, FIG. 28 is a diagram for explaining the principle of the yarn release mechanism 70B, and FIGS. 29A to 29D are diagrams for explaining the operation of the yarn release mechanism 70B.
The yarn release mechanism 70B includes a contact portion 71 provided integrally with the upper end portion of the rotation plate 56 of the yarn holding mechanism 50 described above, and a first portion that contacts the contact portion 71 and rotates the rotation plate 56. A thread release plate 72 that is a second elastic member, and a thread release restriction plate 73 that is a restriction member that reduces the amount of bending of the elastic member.
The contact portion 71 is bent at the upper end of the rotation plate 56 perpendicularly to the plate surface of the rotation plate 56 and extends in the Y-axis direction (back surface side).
The thread release plate 72 and the thread release restricting plate 73 are extended from the threading slide guide 320 toward the surface in the Y-axis direction with the thread release restricting plate 73 on the lower side and stacked vertically. It is fixed to the lower end of the threading slide guide 320 with a screw. The extended tip of the thread release plate 72 is set to be longer on the surface side in the Y-axis direction than the thread release restriction plate 73. When the threading slide guide 320 moves up and down, only the thread release plate 72 is applied. Abuts against the tip of the contact portion 71.
The relative height relationship between the thread release plate 72 and the contact portion 71 is determined when the threading shaft 11 is prevented from descending and only the threading slide guide 320 starts to descend when the threading operation is descending. In this case, the thread release plate 72 is positioned above the contact portion 71, and the thread release plate 72 is positioned below the contact portion 71 when reaching the lowest lowered position of the threading slide guide 320. ing.
Further, the yarn release restricting plate 73 is made of a material that is higher in rigidity than the yarn release plate 72 and hardly bends. The yarn release plate 72 and the yarn release regulating plate 73 are not bonded to each other at least on the free end side. As a result, the yarn release plate 72 can be bent upward without being affected by the yarn release restriction plate 73, but the lower side of the fixed end side contacts the yarn release restriction plate 73. Will be less.

In this structure, in the thread release mechanism 70B, the threading slide guide 320 and the threading shaft 11 are simultaneously lowered during the threading operation, and only the threading slide guide 320 continues to be lowered from the middle. When the yarn release plate 72 is brought into contact with and urged against the contact portion 71 from above, the yarn release plate 72 can be bent upward without being affected by the yarn release regulating plate 73, and therefore the full length of the extension length L1. Will be bent (FIG. 29A). At this time, the moment that the thread release plate 72 exerts on the rotating plate 56 with the refracting portion 55a of the main body plate 55 as a fulcrum is much smaller than the moment that the pressing spring 58 exerts on the rotating plate 56. The spring constant of the pressing spring 58 and various dimensions of the main body plate 55, the rotation plate 56, and the thread release plate 72 are set. For this reason, even if the thread release plate 72 urges the contact portion 71, the thread release plate 72 keeps the posture in contact with the main body plate 55 and continues to hold the sewing thread. The yarn release plate 72 bends upward to avoid the contact portion 71 and reach below the contact portion 71 (FIG. 29B). At that time, the threading shaft 11 is rotated by the action of the threading cam mechanism 340, and the threading hook 20 moves forward to enter the eye hole of a predetermined sewing needle, and the sewing thread held by the thread holding mechanism 50 is captured. To do. The entire yarn holding mechanism 50 is tilted somewhat clockwise by the action of the yarn holding mechanism support mechanism 60. However, in FIG. 29B, the yarn holding mechanism 50 is not shown in a tilted state in order to simplify the explanation of the operation. . Even when the yarn holding mechanism 50 is tilted, the length is set so that only the yarn release plate 72 reaches the contact portion 71 and the yarn release auxiliary plate 73 does not reach.
Subsequently, when the ascending starts from the bottom dead center of the threading slide guide 320, the threading shaft 11 is rotated in the reverse direction by the action of the threading cam mechanism 340, and the threading hook 20 is retracted and the stitches of the sewing needles are rotated. The sewing thread is pulled into the eye hole. At that time, the thread release plate 72 contacts the contact portion 71 from below. At this time, the length of the yarn release plate 72 to be bent is limited to L2 by the highly rigid yarn release restriction plate 73, so that the contact portion 71 is when the yarn release plate 72 contacts from above. A large upward pressing force is also received by the downward pressing force. Further, the thread release plate 72 and the pressure spring are arranged so that the moment that the thread release plate 72 exerts on the rotation plate 56 and the refracted portion 55a of the main body plate 55 as a fulcrum is larger than the moment that the pressure spring 58 exerts on the rotation plate 56. The spring constant of 58 and various dimensions of the main body plate 55, the rotation plate 56, the thread release plate 72, and the thread release restriction plate 73 are set. For this reason, when the thread release plate 72 urges the contact portion 71, the rotating plate 56 integrally formed with the contact portion 71 rotates clockwise with the refracting portion 55a as a fulcrum, and moves away from the main body plate 55 to the thread. Release is performed. (FIG. 29C) The thread release plate 72 rotates and pushes the contact portion 71 and reaches above the contact portion 71. (FIG. 29D).

(Other)
The thread release mechanisms 70, 70A, 70B and the thread holding mechanism 50 are not limited to the threading device 10 used in the multi-needle sewing machine, but include fewer sewing needles (for example, one or two). You may apply to the threading device used for a sewing machine.
Further, the structure of the pinching portion 53 of the thread holding mechanism 50 is not limited to the above, and the rotation plate 56 may be rotatable with respect to the main body plate 55 by a hinge or the like. Further, the clamping unit is not limited to the rotating structure, and a member that can slide relative to the main body plate may be used instead of the rotating plate. For example, normally, the main body plate and the slide plate are opposed to each other so that the sewing thread can be clamped, and at the time of release, the lower end portion of the slide plate is slid upward from the lower end portion of each side wall portion 55a so that the thread can be released. It may be a structure. Even in such a structure, the yarn release mechanisms 70, 70A, and 70B can be applied as they are.

Further, as shown in FIG. 30, an operation lever detection sensor 81 for detecting the position of the operation lever 315 is provided by using an actuator such as a yarn holding solenoid 82 for holding by the holding portion 53 of the yarn holding mechanism 50. The control device 80 may perform control to release the yarn holding by the yarn holding solenoid 82 when the operation lever 315 comes to a predetermined position. At this time, since the sensor passes through the same position twice when the operation lever is lowered and then raised, the control may be performed so that the solenoid is actuated when passing the second time.
The sensor is not limited to detecting the position of the operation lever 315 but may be any sensor that detects the backward movement of the threading hook 20.
By providing these control systems, the same effects as those of the threading device 10 can be obtained, and the mechanical structure can be simplified, so that the reliability of the operation can be improved. Further, it is possible to adjust only the change in the control setting of the yarn release timing, and it is possible to perform more preferable yarn release control.

It is a perspective view of the threading device which is an embodiment of the present invention. It is a front view of a threading device. It is the front view except a part of composition of the threading device. It is a top view except a part of structure of the threading device. It is an expansion perspective view of the lower end part of a threading shaft. It is the perspective view which showed simply the support structure between a main frame, a 1st support mechanism, and a 2nd support mechanism. It is the perspective view seen from the direction different from FIG. 1 of the threading device. It is a rear view of the threading device with a part omitted. It is the side view which looked at the step switching part of the movement operation part from the right side. FIG. 10A is an explanatory view showing the stage switching position by unfolding the first cam, and FIG. 10B is an explanatory view showing the stage switching position by unfolding the second cam. It is a perspective view of a threading operation input mechanism. It is principal part explanatory drawing of a threading cam mechanism. It is a perspective view of a lower threading guide. FIGS. 14A to 14E are diagrams illustrating the relationship between each guide pin and each contact portion when the threading shaft is positioned in an arrangement corresponding to each sewing needle by the positioning mechanism, and FIGS. It corresponds to each arrangement. It is an expansion perspective view of a lower threading guide and an upper threading guide. FIG. 16A is a perspective view of the yarn holding mechanism, and FIG. 16B is a cross-sectional view taken along the line VV in FIG. It is a front view of a thread | yarn holding mechanism and a thread | yarn holding mechanism support mechanism. FIG. 6 is a perspective view showing the operation of the yarn holding mechanism and the yarn holding mechanism support mechanism 60 accompanying the threading operation, and showing a state before the threading operation. FIG. 6 is a perspective view showing the operation of the thread holding mechanism and the thread holding mechanism support mechanism 60 in accordance with the threading operation, and showing the state after the moving body is rotated by the descending of the threading slide guide by the threading operation. FIG. 6 is a perspective view showing the operation of the yarn holding mechanism and the yarn holding mechanism support mechanism 60 accompanying the threading operation, and showing the state where the lowest point of the threading slide guide is reached by the threading operation. It is a perspective view which shows the circumference | surroundings of a thread | yarn release mechanism. It is principle explanatory drawing of a thread | yarn release mechanism. FIGS. 23A to 23D are explanatory views sequentially showing the operation of the yarn releasing mechanism. It is a perspective view which shows the circumference | surroundings of the 2nd Example of a thread | yarn release mechanism. It is principle explanatory drawing of the 2nd Example of a thread | yarn release mechanism. FIGS. 23A to 23D are explanatory views sequentially showing the operation of the second embodiment of the yarn releasing mechanism. It is a perspective view which shows the circumference | surroundings of the 3rd Example of a thread | yarn release mechanism. It is principle explanatory drawing of the 3rd Example of a thread | yarn release mechanism. FIGS. 23A to 23D are explanatory views sequentially showing the operation of the third embodiment of the yarn releasing mechanism. It is a block diagram which shows the other example of a threading device.

Explanation of symbols

1 to 5 Sewing needle 6 Needle bar 10 Threading device 11 Threading shaft 20 Threading hook 50 Thread holding mechanism 51, 52 Thread hook portion 53 Nipping portion 55 Main body plate (holding member)
55b Window part 56 Rotating plate (clamping member)
58 Pressing spring (first elastic member)
60 Thread holding mechanism support mechanism 70, 70A, 70B Thread release mechanism 71 Contact portion 72 Thread release member (second elastic member)
73 Restriction plate (regulation member)
75 engaging member 90 main frame 100 first support mechanism 101 first frame 102 guide shaft 200 second support mechanism 201 second frame 202 guide shaft 300 threading operation input mechanism 310 operation lever (threading operation input means) )
320 Threading slide guide (elevating member)
330 Height adjusting mechanism 331 First guide pin 332 Second guide pin 340 Threading cam mechanism 341 Engaging projection 342 Long hole portion 350 Lower threading guides 351 to 355 Abutting portion 360 Upper threading guide 400 Positioning mechanism 441 Movement operation dial (movement operation part)
420 First cam mechanism 421 First cam 430 Second cam mechanism 431 Second cam

Claims (4)

A threading hook that penetrates through the eye hole of the sewing needle by advancing and captures the sewing thread, and inserts the sewing thread captured by the retreating into the eye hole;
A threading shaft for holding the threading hook at the lower end;
A threading operation input mechanism for inputting an operation for causing the threading device to perform the threading operation;
An elevating member that moves up and down by an operation to the threading operation input mechanism, and that imparts a rotational motion to the threading shaft;
A thread holding mechanism for holding the sewing thread inserted through the sewing needle by holding the sewing part biased by the first elastic member;
A thread release mechanism for releasing the sewing thread held by the thread holding mechanism;
In a threading device for a sewing machine comprising:
The elevating member includes a second elastic member that engages with the clamping portion when the elevating member moves in the vertical direction.
When the elevating member descends, the second elastic member engages so as to act in a direction in which the sewing thread of the clamping portion is not released,
When the elevating member rises, the second elastic member urges the clamping portion in a direction to release the clamping of the sewing thread,
A threading device for a sewing machine, wherein the sewing thread is released when the threading hook moves backward. A threading hook that penetrates through the eye hole of the sewing needle by advancing and captures the sewing thread, and inserts the sewing thread captured by the retreating into the eye hole;
A threading shaft for holding the threading hook at the lower end;
A threading operation input mechanism for inputting an operation for causing the threading device to perform the threading operation;
An elevating member that moves up and down by an operation to the threading operation input mechanism, and that imparts a rotational motion to the threading shaft;
A thread holding mechanism that holds the sewing thread inserted through the sewing needle by the clamping member biased by the first elastic member;
A thread release mechanism for releasing the sewing thread held by the thread holding mechanism;
In a threading device for a sewing machine comprising:
An engaging member provided on the elevating member;
A second elastic member provided on the clamping member so as to engage with the engaging member of the elevating member when the elevating member moves in the vertical direction;
When the elevating member descends, the second elastic member engages so as to act in a direction in which the sewing thread of the clamping portion is not released,
When the elevating member rises, the second elastic member urges the clamping portion in a direction to release the clamping of the sewing thread,
A threading device for a sewing machine, wherein the sewing thread is released when the threading hook moves backward.   3. The threading device for a sewing machine according to claim 1, further comprising a restricting member that reduces a bending amount of the second elastic member. 4.   The said clamping part is provided with two clamping members which have the clamping surface which mutually opposes, The window part which can visually recognize the held sewing thread was provided in at least one clamping member, The any one of Claim 1 to 3 characterized by the above-mentioned. A threading device for a sewing machine according to claim 1.

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